how can i find out how an Xbox is modded?

my cousin had his Xbox 360 flashed, he had someone he knows who lives near him flash it for him, and he gave him a few backups.

my cousin wants new games, and i burned Gears 3, and NBA 2K12. my cousin came with his console, but the games didn't work. i put the games in, and they said update needed cannot be found. so i put my retail Gears 3 in, and it updated (offline).

now, when i tried to launch the backups, the screen turns black for a second, and it just went back to the dashboard. his other game backup, NCAA football 2011, works. but gears 3 and nba 2k12 doesn't.

so, i guess i have to update his DVD drive firmware, but i have no idea where to start for this. how can i find out which drive he has, and what firmware it's on, and what i need to do to update it.

the person who originally modded his Xbox is not really reliable for information. thanks

You should of flashed the drive back to original firmware, then updated the dash, then flashed it back to the newest ixtreme. Check out the jungleflasher tutorial to find out what drive you have and how to flash it.